Bioplastics are an increasingly well-know alternative to petroleum-based plastics. Derived from sugars, compounds such as PLA (polylactic acid), PHB (poly-3-hydroxybutyrate), and PHA (polyhydroxyalkanoates) have found their way into the marketplace and the demand for them is growing. Similar demands are being made for biochemicals made from sugars instead of fossil oil supplies. To compete, however, the bioplastic and biochemical industries require sugars that are decolorized and highly refined to enable their proprietary microbes or chemical catalysis technology to produce the initial chemical derivatives, such as succinic acid, for synthesizing plastics. For cellulosic and lignocellulosic sugar suppliers, this can necessitate clarifying and reducing the toxic compounds in the sugar streams during and/or after pretreatment to assure that the custom-designed sugar stream meet the necessary specifications for these industries. Inhibitors such as furfural, HMF (hydroxymethylfurfural), acetic acid and other phenolics must be reduced to an acceptable level.
The use of activated carbon has been used to sequester color in the chemical industry as well as reduce inhibitors found in various sugar broths. To date, however, clarification and reduction of inhibitors in sugar streams derived from cellulosic or lignocellulosic materials has been limited to dilute streams. This refinement is often only partially effective and can increase the cost of the sugars due to the high cost of evaporation later to concentrate the sugars. There is a need for improve carbon filtration methods that can be used on a concentrated sugar stream from cellulosic or lignocellulosic biomass to reduce pigmentation as well as the inhibitor concentration within the sugar stream.